Under slab dust collection

[brianpgriset]

I did underground dust collection. 6” schd 40 pvc. It’s been in the ground 3 years no leaks or issues. I have not been using it as I am still finishing the inside but I’m really glad I did it and suggest you do too. I’ll snap some pics tomorrow.

 

[Norcal]

Might consider wearing adult diapers when they tell you the price of the fittings you might need them. All jokes aside my neighbor 3D printed his DC fittings because they are so expensive.

 

[jrsevy1]

We built a new home in 2023 and my shop is below our 3 car garage, 800 ft2. I installed 6" PVC sewer pipe to all my machines under slab. The pipe is buried in gravel and above that is 2" of XPS insulation, hydronic PEX heating pipe and then 4" of reinforced concrete slab coated with quartz imbedded epoxy. I put 6" threaded hubs as my connectors at the floor but prior to the pour, I wrapped the pipe with 1/2" EPDM foam so I could add a fitting at floor level without breaking the concrete around the pipes to do so. I found that Supply House sells 6" sewer connectors where ribbed rubber slides into a sewer pipe, which fits perfectly into the 6" hub and seals. I decided that would be better than rigid sched 40 PVC that could crack if struck hard, or pain in my foot from smacking into them. The rubber on the sewer connectors flex.

The advantages of buried DC piping is huge. It's naturally grounded, it's quieter, invisible, and not a dust magnet like overhead pipe. I reduced to either 4" or 5" DC hose within a few feet of each machine, where all are on mobile bases.

My DC is a Harvey Gyro with intake near the floor, so I have around 3' of vertical pipe for better air movement than running overhead and down to machines. Considering that air pulls down into the DC pipe, rather than up, that probably almost negates the 3' vertical. I get great airflow at every machine.

I added a couple of cleanouts at the WYE fittings but could add a machine there. My floor pipe covers are 6" threaded caps with 1/4" brass threads in the middle. Ordered 8" x 1/16" stainless rounds on eBay, drilled in the middle and used stainless machine screws to fasten to the PVC caps. Future owners could repurpose my shop for any living space or whatever.

If you have a chance to do under slab DC piping, I think it's a no brainer.

 

[Wiebster]

That sounds amazing. In hindsight and a lot of flak from others, I wish I had kept going with 6” right to each machine instead of branching off with 4”. I was thinking about clogs, not airflow. I’m still really glad I installed it underground and I’m convinced that it’s still going to work just fine. The 6” and 8” pvc fittings are ridiculously expensive. I’m not convinced that pvc self grounds because it doesn’t conduct electricity but I may be wrong. I thought I would still run a ground wire through the pipe. Have you heard or read otherwise? Sounds like you have a really slick DC. I’ll post how mine works when it’s up and running.

 

[jrsevy1]

I wouldn't run a wire through the pipe. It would just catch shavings and start to build a dam until the pipe is clogged or flow severely restricted at a turn. I never experience static shocks. DWV (Drain, Water & Vent or sewer pipe) PVC pipe and fittings are a lot cheaper than sched 40 PVC. That's what I used. Sched 40 PVC is overkill for DC when DWV pipe works.

 

[glandjr]

We built a new home in 2023 and my shop is below our 3 car garage, 800 ft2. I installed 6" PVC sewer pipe to all my machines under slab. The pipe is buried in gravel and above that is 2" of XPS insulation, hydronic PEX heating pipe and then 4" of reinforced concrete slab coated with quartz imbedded epoxy. I put 6" threaded hubs as my connectors at the floor but prior to the pour, I wrapped the pipe with 1/2" EPDM foam so I could add a fitting at floor level without breaking the concrete around the pipes to do so. I found that Supply House sells 6" sewer connectors where ribbed rubber slides into a sewer pipe, which fits perfectly into the 6" hub and seals. I decided that would be better than rigid sched 40 PVC that could crack if struck hard, or pain in my foot from smacking into them. The rubber on the sewer connectors flex.

The advantages of buried DC piping is huge. It's naturally grounded, it's quieter, invisible, and not a dust magnet like overhead pipe. I reduced to either 4" or 5" DC hose within a few feet of each machine, where all are on mobile bases.

My DC is a Harvey Gyro with intake near the floor, so I have around 3' of vertical pipe for better air movement than running overhead and down to machines. Considering that air pulls down into the DC pipe, rather than up, that probably almost negates the 3' vertical. I get great airflow at every machine.

I added a couple of cleanouts at the WYE fittings but could add a machine there. My floor pipe covers are 6" threaded caps with 1/4" brass threads in the middle. Ordered 8" x 1/16" stainless rounds on eBay, drilled in the middle and used stainless machine screws to fasten to the PVC caps. Future owners could repurpose my shop for any living space or whatever.

If you have a chance to do under slab DC piping, I think it's a no brainer.

Hi, This sounds exactly like I'm attempting to do now. can you verify if these fittings are the ones you had success with?

https://www.supplyhouse.com/sh/control/viewCart

the black connector went into a female fitting or in a straight pipe?

When you come up through slab its with a straight pipe or say a female 45 end? I have just about the room to try and get the female threaded connector flush (and taped over for pour) to the final top surface. I'm planning on wrapping with several layers of sill sealer foam (where did you get the 1/2" EPDM foam) and leaving unglued to be able to modify if I need to. but I am looking for the Pro look of what you did here! Thank you!

 

[Pen & Wrench]

Can you get by with 4 inch pipe. Well, there's dust collection and then there's dust collection. You can do some research to figure out how many cfm is required for various machines. There's lots of good information but I really like this website, Bill Pentz: https://billpentz.com/woodworking/cyclone/index.php. And Onieda has some really good info and some really good machines, and of course there are others.

It really gets down to how good a system you want to have. The Pentz website has information that will give you an idea how effective your dust collection system will be depending on how well the collection hoods are made, and how many cfm is available, I used to think that a 4 inch pipe would be pretty much good enough for just about any tool, but there are some instances where a 6 inch pipe will move quite a bit more air and get a higher percentage of the dust at the machine. I don't think a system has to be absolutely 100% effective, but I think we should strive to make it as good a performing system as we are reasonably able to do. I have a Grizzley 5 inch blower with bags, that can handle 2 4 inch pipes, and I would really like to get a cyclone system with really good filter bags, but that is not in the budget for me until I get a new shop built.

 

[lrp2000]

I wouldn't run a wire through the pipe. It would just catch shavings and start to build a dam until the pipe is clogged or flow severely restricted at a turn. I never experience static shocks. DWV (Drain, Water & Vent or sewer pipe) PVC pipe and fittings are a lot cheaper than sched 40 PVC. That's what I used. Sched 40 PVC is overkill for DC when DWV pipe works.

Did you take any photos of what you did? I’m getting ready to start a home shop and have the ability to do whatever I want

 

[Stuart in MN]

I'm late to the conversation but I'm pretty sure they ran dust collection pipes under the slab on the New Yankee Workshop TV show with Norm Abram. All of those episodes are now available on YouTube, you could go back and look at the earlier episodes to see if they show any detail.

 

[Wiebster]

Here are some photos that I took before and after the pour. Unfortunately I can’t tell you if my system works well or not as I’m still building the shop and haven’t hooked up the dust collector or the tools. I ran a 6” straight main line and branched off with 4” for each tool. Plenty of people on here told me that the pipes had to be bigger but I guess we’ll find out. I plan on putting the dust collector on the outside of the shop under my shed roof the runs the length of it. That is why you see the 6” come up out of the ground outside the concrete forms. I cut everything a 1/4” below the top of concrete, plugged and taped them, and they went right over the top. The pipes started to show themselves as the concrete dried and there was traffic over them. I hope this helps.

 

[lrp2000]

This is awesome! Do you have a sketch of how your shop will be laid out?

I'm late to the conversation but I'm pretty sure they ran dust collection pipes under the slab on the New Yankee Workshop TV show with Norm Abram. All of those episodes are now available on YouTube, you could go back and look at the earlier episodes to see if they show any